If they are 20# negative and I can't ditch their weight, one of us isn't coming up.
One other thought: I have no idea how to operate a drysuit. I don't own one, I have never used one and. if I had to rescue someone who was wearing one. things would probably turn south.
No offense Richard, but if I ever need to be rescued, I REALLY hope someone else is available.
I suppose you could just ditch your gear and use the wetsuit for flotation, but that would be really expensive.
Just food for thought, but if you had a reel, you could attach it to the rig before dropping it and, if you had a SMB, attach it to the free end and have what would essentially be a buoy marking your gear and helping to hold you in position until help arrived. It might not be practical, but I might give it a try one of these days to see if it's workable.
If your wetsuit loses 20# of buoyancy at depth, by definition, you are 20# overweighted at that depth. There's nothing you can do about it, you are overweighted.
There IS something you can do about it, if you take proactive solutions into account. What you can do, upon recognizing that you have an issue, is prevent it. If your wetsuit loses buoyancy to the point that it becomes a problem, stop diving to those depths wet. Either get a drysuit, etc. to provide static gas volume and redundant buoyancy, accept the risks, or don't dive that deep. I've also seen some older books on diving that advocate removing some weight at depth and hanging it on the line for recovery during ascent, but that obviously introduces new risks (can't get back to the line and have to make a buoyant ascent) that might well be considered unacceptable.
I don't think an SMB or lift bag is going to help. How do you manipulate your buoyancy, the victim's buoyancy (assume their bladder is hosed), hold the reg in their mouth, maintain control of their body and still mess with a bag?
I don't think you're right. It would certainly take practice, but if it were me, I'd dump the gas from my wing (if any), open both drysuit dump valves (if any) and use the bag to control both of our ascents, so there would only be one air space to manage.
More likely though, I'd just use my wing and drysuit to provide the lift. More likely still, if my buddy's wing failed, he'd be able to use his own drysuit for buoyancy and aside from seeing his inflator hose get "the bird", I probably won't even hear about the issue until he started bitching about his #@$&! wing on the surface.
It would certainly be a more complex rescue if it were an unconsious diver with a compromised wing, but multiple failure scenarios are always more of a challenge. If it were just a wing failure, I wouldn't expect to have to hold anyone's reg in.
But not being able to get positive at the surface without ditching the rig does not improve the odds.
IMHO, the important thing in an emergency is that you're able to stay buoyant at the surface. Who gives a flying rat part how you do it, so long as it works well. If you're concerned with being able to rescue someone, I recommend looking past "plan A". I can think of a half dozen ways to get someone overweighted to the boat using the gear I typically have with me, and could confidently adapt to their equipment set up if I need to do it.
I think the AL80 is the way to go for you with your buoyancy characteristics, especially since it doesn't appear that you need the extra volume of steel tanks. The tank should fit the type of diving you do and AL80 seems to be perfect fit in this case.
I agree. It doesn't necessarily need to be an AL80, but you shouldn't be diving with gear that causes you to be overweighted without a clear plan for establishing buoyancy when you need to. Sometimes ditchable weight is the right answer for a given situation... other times, it might be redundant buoyancy like a dual bladder wing, drysuit, or (though I wouldn't consider it anything better than a backup plan) a SMB or lift bag.
